To improve performance without increasing size, a sealing device comprises a seal body (6) sealing a clearance (5) between the periphery of the shaft hole (3) of a housing (2) and a shaft (4) inserted into the shaft hole (3) and the sound insulating seal (7) insulating sound transmitted through the clearance (5), the seal body (6) comprises a bellows part (10) between a mounting part (8) fitted to the housing (2) and a seal lip part (9) contacting with the shaft (4), the sound insulating seal (7) comprises a sound insulating member (20) disposed at the inner peripheral side of the mounting part (8), and the sound insulating member (20) is held to the seal body (6) in the state of contacting with the mounting part (8) at its outer peripheral part (20a) and with the seal lip part (9) at its inner peripheral part (20b).